Analysis Of Bolton And Occlusion In Dalian

Objective:This study is aim to establish the norm value of Bolton in Dalian teenagers, then distribute the Bolton anterior and overall ratios among ClassⅠ,Ⅱ,Ⅲmalocclusion groups. At the same time, provide the reference for diagnoses in orthodontics.Methods:120 cases of normal occlusion dental model in Dalian were selected, with 60 boys and 60 girls.120 dental casts of orthodontic patients were selected randomly,40 subjects of Angle classⅠ,ⅡandⅢwere arranged with half man and half woman. Each tooth crown mesiodistal size between the first molar and the opposite molar of 240 dental casts was measured by electric calliper. Anterior ratio and overall ratio were calculated, then were analysed with statistic methods. 240 casts were divided into a Bolton big, a Bolton normal and a Bolton small group according to the Bolton normal value puls or minus one standard deviation, then get the statistic analysis.Results:1. The norms of Bolton anterior and overall ratios in Dalian teenagers were established, simultaneity the regressive equations were built.2. No statistically significant sex difference was found between anterior ratio and overall ratio in the three malocclusion groups and normal occlusion, but the means of males was lager than that of the female. As a result, females and males were combined to be a group.3. The distribution of number in Angle groups was as follows: the number of patients in the Bolton normal group was the most, it was the least in the Bolton big group.4. Statistically significant differences were found between classⅢand other groups in Bolton big group for the overall ratio.Conclusion:1. The norms of Bolton anterior and overall ratios in Dalian teenagers were established. The anterior ratios is 78.42%±2.84%,and overall ratios is 91.54%±2.22%.2. The regressive equations are used to calculate the discrepancy of maxillary and mandibular tooth, provide the reference for clinical diagnoses.3. No significant sex differences was found in the anterior and overall ratios between normal occlusion and Angle classⅠ,Ⅱ,Ⅲ.4. Statistically significant differences were found between classⅢand other groups for the overall ratio, classⅢandⅡfor the anterior ratio. So the analysis of Bolton index was indispensable in our diagonosis and design.